A number of systems of this type are already known in which the fixed electrical supply means are comprised of an insulated cable with multiple conductors which is permanently fixed and the movable lighting means are comprised of a connector provided with two conductive prongs which are capable of perforating the insulator and enter into electrical contact respectively with each of the cores of the electrical supply cable. It is understood that the connection head can thus be connected to the cable at any convenient point. However, it appears that an installation of this type is ill-suited to connecting certain movable lighting means such as picture rails to light pictures or lighting tubes which have to be positioned, for instance, in an object display window and which have to be held firmly in place.
Another disadvantage of certain of these installations is that penetration by the ends of the prongs in the shape of pins in the cores of the electrical conductors can entail severing of one of the cores and thus make the installation unusable.